An exposure device for exposing a photoreceptor, includes: data electrodes disposed for each of a plurality of columns parallel to a moving direction of the photoreceptor; selected electrodes disposed for each of a plurality of rows perpendicular to each of the data electrodes; light emitting element arrays including light emitting elements disposed near intersection points between the data electrodes and the selected electrodes in intersections between the data electrodes and the selected electrodes, the light emitting elements being linearly arrayed; a driving signal output circuit for generating a driving signal based on an image signal to supply the driving signal to the light emitting element arrays; and a column selection unit for switching the light emitting element arrays to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An exposure device for exposing a photoreceptor, comprising: a plurality of data electrodes disposed for each of a plurality of columns parallel to a moving direction of the photoreceptor; a plurality of selected electrodes disposed for each of a plurality of rows perpendicular to each of the data electrodes; a plurality of light emitting element arrays which include a plurality of light emitting elements disposed near intersection points between the data electrodes and the selected electrodes in intersections between the data electrodes and the selected electrodes, the plurality of light emitting elements being linearly arrayed; a driving signal output circuit for generating a driving signal based on an image signal to supply the driving signal to the light emitting element arrays; and a column selection unit for switching the light emitting element arrays to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.
2. The exposure device according to claim 1 , wherein the driving signal output circuit time-sequentially supplies the driving signals corresponding to each of the predetermined number of light emitting elements of the light emitting element array, and wherein the exposure device further comprises: a dividing circuit for dividing each driving signal so as to correspond to the predetermined number of light emitting elements of the light emitting element array; and a division control circuit for controlling application of the driving signals to each of the predetermined number of light emitting elements according to time-sequential timing of the driving signal.
3. An exposure device for exposing a photoreceptor, comprising: a plurality of data electrodes disposed for each of a plurality of columns parallel to a moving direction of the photoreceptor; a plurality of selected electrodes disposed for each of a plurality of rows perpendicular to each of the data electrodes; a plurality of light emitting element arrays which include a plurality of light emitting elements disposed near intersection points between the data electrodes and the selected electrodes in intersections between the data electrodes and the selected electrodes, the plurality of light emitting elements being linearly arrayed; and a column selection unit for designating a selected electrode of a certain predetermined column among the plurality of selected electrodes and setting selected electrodes of the other columns to undesignated selected electrodes during image forming executed on a recording medium, for executing the image forming on the recording medium only by a light emitting element of a column connected to the designated selected electrode, and for switching the light emitting element arrays to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.
4. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column every time the image forming executed on one recording medium is ended.
5. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column every time the image forming executed on a plurality of recording media is ended.
6. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column every time the image forming executed on a predetermined number of recording media within a predetermined period is ended.
7. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column when a light emitting element corresponding to the designated selected electrode reaches a predetermined temperature.
8. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column when an applied current flowing through the light emitting element is reduced to a predetermined value due to time degradation of the light emitting element.
9. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column when a voltage applied to the light emitting element increases to a predetermined value due to time degradation of the light emitting element.
10. The exposure device according to claim 3 , wherein the column selection unit switches the designating of the selected electrode to the selected electrode of another column every time an image forming apparatus is started up.
11. The exposure device according to claim 3 , wherein a lighting circuit of the light emitting element arrays includes a plurality of transistors connected to the data electrodes.
12. A method for operating an exposure device which exposes a photoreceptor, the exposure device including a plurality of data electrodes disposed for each of a plurality of columns parallel to a moving direction of the photoreceptor; a plurality of selected electrodes disposed for each of a plurality of rows perpendicular to each of the data electrodes; and a plurality of light emitting element arrays which include a plurality of light emitting elements disposed near intersection points between the data electrodes and the selected electrodes in intersections between the data electrodes and the selected electrodes, the plurality of light emitting elements being linearly arrayed; wherein the method comprises: designating a selected electrode of a certain predetermined column among the plurality of selected electrodes and setting selected electrodes of the other columns to undesignated selected electrodes during image forming executed on a recording medium; executing the image forming on the recording medium only by a light emitting element of a column connected to the designated selective electrode; and switching the light emitting element arrays to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.
13. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column every time the image forming executed on one recording medium is ended.
14. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column every time the image forming executed on a plurality of recording media is ended.
15. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column every time the image forming executed on a predetermined number of recording media within a predetermined period is ended.
16. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column when a light emitting element superposed in the designated selected electrode reaches a predetermined temperature.
17. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column when an applied current flowing through the light emitting element is reduced to a predetermined value due to time degradation of the light emitting element.
18. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column when a voltage applied to the light emitting element increases to a predetermined value due to time degradation of the light emitting element.
19. The method according to claim 12 , wherein the switching of the light emitting element arrays to be selected comprises switching the designating of the selected electrode to the selected electrode of another column every time an image forming apparatus is started up.
20. An exposure device for exposing a photoreceptor, comprising: a light emission unit including a plurality of light emitting element arrays which comprise a plurality of light emitting elements which are linearly arrayed, and a plurality of first switching elements disposed so as to correspond to the plurality of light emitting elements, respectively, the light emission unit having a structure in which the light emitting element arrays are arranged in parallel; a driving signal output circuit for generating a driving signal based on an image signal to supply the driving signal to the light emission unit; a column selection unit for controlling turning ON/OFF of the plurality of first switching elements for each light emitting element array to select the light emitting element array to which the driving signal is applied via the first switching elements so as to correspond to each of predetermined number of light emitting elements, among the plurality of light emitting element arrays; a dividing circuit including a circuit for dividing each of the driving signals supplied from the driving signal output circuit so as to correspond to the predetermined number of light emitting elements of the light emitting element array, and a plurality of second switching elements disposed so as to correspond to each of the divided driving signals to interrupt application of the divided driving signals to each of the predetermined number of light emitting elements; and a division control circuit for controlling turning ON/OFF of the second switching elements by timings which are different from one another, to control the application of the divided driving signals to each of the predetermined number of light emitting elements.
21. The exposure device according to claim 20 , wherein the column selection unit switches the light emitting element array to be selected based on a lighting situation of each of the light emitting elements of each of the light emitting element arrays.
22. An image forming apparatus for forming an image on a recording medium, comprising: a photosensitive drum including a photoreceptor; and an exposure device for irradiating the photoreceptor of the photosensitive drum with a light based on an image signal to expose the photoreceptor, and for executing printing on the recording medium according to the image signal, wherein the exposure device comprises: a light emission unit including a plurality of light emitting element arrays which comprise a plurality of light emitting elements which are linearly arrayed, and a plurality of first switching elements disposed so as to correspond to the plurality of light emitting elements, respectively, the light emission unit having a structure in which the light emitting element arrays are arranged in parallel; a driving signal output circuit for generating a driving signal based on an image signal to supply the driving signal to the light emission unit; a column selection unit for controlling turning ON/OFF of the plurality of first switching elements for each light emitting element array to select the light emitting element array in which the driving signal is applied to each of the light emitting elements via the first switching elements, among the plurality of light emitting element arrays of the light emission unit; a dividing circuit including a circuit for dividing each of the driving signals supplied from the driving signal output circuit so as to correspond to the predetermined number of light emitting elements of the light emitting element array, and a plurality of second switching elements disposed so as to correspond to each of the divided driving signals to interrupt application of the divided driving signals to each of the predetermined number of light emitting elements; and a division control circuit for controlling turning ON/OFF of the second switching elements by timings which are different from one another, to control the application of the divided driving signals to each of the predetermined number of light emitting elements.
23. The image forming apparatus according to claim 22 , wherein the column selection unit switches the light emitting element array to be selected based on a predetermined condition according to a lighting situation of the plurality of light emitting elements of each of the light emitting element arrays.
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September 27, 2007
May 21, 2013
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